Expression of genes related to inflammation – IL-6, IL-8, and IFN-γ in monitoring ustekinumab therapy: preliminary results

Introduction
Psoriasis is classified as an inflammatory and autoimmune disease. Changes in the concentration profile of some cytokines, such as interleukin-12 (IL-12), IL-23, and IL-17, play a key role in its pathogenesis. IL-6, IL-8 and interferon- g (IFN-g) are also hallmark cytokines in a psoriatic cytokine network. Cytokine-blocking drugs, which are a part of the inflammatory cascade, are now increasingly popular. One of them is ustekinumab, directed against IL-12 and IL-23, but also indirectly against other interleukins, which take part in the inflammatory reaction. Due to the complexity of inflammation pathways, new molecular markers are still being sought. Regardless of the type of therapy used, they allow to determine its effectiveness, signal the lack or loss of sensitivity to treatment.

Aim
To evaluate the expression profile of genes related to the inflammatory reaction – IL-6, IL-8, and IFN-g – in patients with psoriasis, depending on the duration of ustekinumab therapy.

Material and methods
The material for the study was the PBMCs of 14 patients suffering from psoriasis who were treated with ustekinumab. Monitoring was performed after 16, 28, and 40 weeks of therapy. The gene expression of IL-6, IL-8, and IFN-g was measured using the RT-qPCR method.

Results
There was a statistically significant increase in the expression of IL-6 and IFN-g genes in psoriasis patients, depending on the duration of ustekinumab therapy.

Conclusions
The increase in mRNA copy numbers of the pro-inflammatory IL-6 and IFN-g genes in the following weeks of therapy may suggest that patients treated with ustekinumab may progressively develop resistance to biological treatment.